Relay system



Aug. 14, 1928.

' H. P. SLEEPER RELAY SYSTEM Filed April 11. 1922 R O T N E V m Harvqy EJ/eeper ATTORNEY Patented Aug. 14, 1928.

HARVEY r. SLEEPER, or wInKINsnU'ne,

PATENT orr cs.

IPENNSYLVANIA, ASSIGNOR TO \fESTING- HOUSE ELECTRIC 8c MANUFACTURINGCOMPANY, A CORPORATION 0F PENNSYL- VANIA.

RELAY SYSTEM.

Application filed April 11, 1922. Serial No. 551,448.

My invention relates to electrical pro tective systems and particularlyto relay systems for protecting distribution systems.

One object of my invention is to provide a relay system for protecting aplurality of parallel-connected transmission circuits extending betweentwo predetermined points of an electricalsystem. g Z 1 Another objectofmy invention is to provide a system, of the above-indicated character,wherebythe transmission systems may be protected according to apredetermined unbalance between the currents traversing the respectivecircuits arranged in pairs.

Another object of my invention is to provide a relaysystem, of theabove-indicated character, in which a relay,that is associated with twopredeterminedcircuits to controlthe disconnection of the circuits uponthe occurrence of an unbalance exceeding a predetermined amount betweenthe circuit currents, shall be rendered inoperative to control theassociated circuitupon the disconnection of either circuit fromthe-system by reason of a condition in that circuit producing anunbalance between the currents traversing the associated circuit.

Another object of my invention is to provide a system, of theabove-indicated character, in which the relay shall selectively controlthe disconnection of either associated circuit upon the occurrence ofsuch conditions in either circuit as would cause a variation beyond apredetermined amount between the circuit currents. A further object ofmy invention-is to provide a system, of the abovedndicated character, inwhich the control balance relay shallbe not only selective in itsoperation but shall also embody an inverse-time 616-? ment initsoperation. 7 i i i United States Patent-No. 1,286,415, is.

sued Dec. 3, 1918 to F. ERicketts, and as signed to the "WestinghouseElectric and Manufacturing Company, discloses an induction disc-typerelay embodying an inverse'time function in its operation that isobtained and controlled bymeans of a saturable transformer that operatesto control the torque developed in the relay.

The saturable transformer permits a torque to be developed in the relaythat is proportional to the value of the current traversing the relay upto a predetermined value at which the transformer becomes saturated.lVhen the current traversing the relay exceeds the value at which thetransformer becomes saturated, the torque de veloped in the relayremains. constant, ir-

respective or increase in the value of current traversing the relay, byreason of the regulating eifect of. the saturated transformer, I V Y Inpracticing my invention, I employ. a saturable transformer, or "torque.compensator, as it is commonly known and which is described in theabove-mentioned'Ricketts patent, and apply it to a relay of the induc-.

' tion type in such manner as to cause therelay to have both adirectional and a. timeelement feature. 7

The single figure of the accompanying drawing is a diagrammatic view'ofaportion of, an. electrical system illustrating three parallelconnectedconductors of respective transmission circuits and a relay system forprotecting such circuits upon'the occurrence of such faults in-any oneof the conductors as wouldcause an increase, decrease or reversal ofcurrent that would tend to disturb a predetermined balance between thecurrents that might traverse the respective'vcircuits.

As is illustrated in the accompanying drawing, energy is supplied from asource of.

electromotive force 10 to a plurality of transmission circuits 11, 12and 13 through associated circuit interrupters 14, 15 and 16,respectively. v

The circuit 11 is provided with an overload relay 17 and a balance relay18.]The circuit 12 is similarly provided with an overload relay19 and abalance relay'20, and the circuit 13 is likewise provided with an over--load relay 21 and a balance relay 22.- i

Therelays are inductivelyQenergized from the respectivecircuits throughcurrent transformers 23, 24 and .25, respectively. Theoverloadrelays 17,19 and 21 are adapted to, close their respective switches 26, 27 and 28when energized to a predetermined degree and for a predeterminedinterval'oftime corresponding thereto, lrrespect ve ofthedirection ofpower traversing the associated,

circuits. Q i The balance relays 18, 20 and 22 comprise,

respectively, a magnetizable core member' 30, provided with twodifferentially-acting windings 31 and 32, and a selectively'energizedwinding 33 that is adapted to 00- llt operate with thedifierentially-acting windings to control the direction of movement 01,ainovable disc member 34. v V I The disc member 34 controls a bridgingmember 35 that is adapted, when actuated in one direction, to engage twocontact members 36 and, when actuated in the other direction, to engagetwo contact men'ib'ers 37. The balance relays further comprise,respectively, asaturable transformer 38 that is provided with twodillerentially-actin'g primary-windings 39 and 40 and a single secondarywinding 41 that is connected to the relay winding 33.

The overload relays 17, 19 and 21 are arranged to control the respectivecircuits associated therewith. Each of the balan'cerelaysl8', 20 and 22,however, is arranged to control two of the transmission circuits.

The balance'relay 18 controls the circuits 11 and 12, the balance relay20 controls the circuits '12 and 13 and the balance relay 22 controlsthe circuits 11 and 13.

Upon the occurrence of faulty conditions i in one ofthe circuits, therelays will selec tively control the operation of the associatedinterrupter. Each of the interrupters is providedwith a trip coil 42 andthree interlock switches 43, 44 and 45'.

In order to indicate to an attendant in the station the automaticdisconnection of a circuit by reason of a faulty condition, a bell, orother indicating device, 46 is employed which is operated whenever oneof the interrupters is automatically opened. A transfer relay 47 isemployed to com-01 the circuit of the bell, or other indicating device.I

The relay 47 comprises a 'sw'tch 48 that normally is closed and a switch49 that normally is open. The relay fur'the'r com-prises an operatingcoil 50 which, when energized,

actu'ates the switches 48 and 49 to opposite positions, at whichpositions the switche'sj'a re maintained by a latching member 51'. Thelatching niembfer 51 is actuated. to permit the resetting of the relayin its initial posi tio n' upon the ene'rgiz'ation of a resetting coil52. A push hutt on switch 53 is provided to control the circuit or theresetting co'il.

By tracing the circuits of the operating coils of the balance relays, itwill be noted that the relays are energized in accordance with thedegree of unbalance between the currentstraversing the associatedcircuits. In considering the connections of the relay 18, for example,it will be observed that the windihgs 31 and 39 are energized from thecurrent transformer 23, whereas the windings 32, and 40 are energizedfrom the current transformer 24. The windings 39 and 40 are connected intheir 'respective'circuits to be difierentially effectivein'energizingfthe secondary winding 410i the saturable transformer.

The windings 31 and 32 are similarly differentially effective inmaintaining a flux distribution in the magnetizable core member 30.Since the winding 41 is energized in accordance with the ditlerencebetween the degree of .en'erg'izaabh or the windings ber 34, dependingupon which set of windings 31 and 39 or 32 and 40 is energized toagreater degree;

The saturable transformer 38 introduces a time element in the operationof. the balance relay 18 by'reason of its saturable char? a'ct'er anditslimiting effect upon the value of the current that may be caused totraverse the circuit including the secondary winding 41. I

, The transf rmer 38 also serves to introduce an electrical angulardisplacement be tween the flux established by the winding 33 and theresultant flux established by the differentially-acting .windings 31 and32, thereby rendering the induction .relay 18 operative. The necessity.for shading pole pieces or other corresponding means for introducing anangular displacement between two of the fluxes to produce a rotativetorque in the disc member is thus obviated.

The inte'r'rupters 14, 15 and 16, when closed, effect the closing of theassociated interlock switches 43, 44 and 45 to complete the variouscircuits controlled thereby. The switches 43 of the interrupterscontrol, the circuit of the associated trip coil 42. The switches 45 ofthe interrupters 14 and 16, when closed, control the energizing circuitfor the control switch iof the balance relay 22. The switches 44 oftheinterrupters 15 and '16 control the energizing circuittor the controlswitch of the balance relay 20 and, similarly, the interlock switch 44of the inte'rrupter 14 and the switch 45 of the interrupter 15 controlthe energizingcircuit of the balance relay 18. The switch 45 of theinterrupter 14 similarly controls the en ergizin circuit for theoverload relay 17. Similarly, the switch 45 of the interrupter 15 andthe switch 44 of the interrupter 16 control the energizing, circuits"for the switches of the associated overloadrelays 19 and 21,respectively. I I

If the interrupters 14, 1'5 and 16 are all closed to connect the feederor transmission circuits to thesystemyand a fault should'occur upon theconductor 11 that would cause such an unbalance between the currentstraversing the conductors 11 and 12 as to exceed a predetermined ratiobetween such currents, the windings 39 and 31 would be enercui ts.

gized to a greater degree thanthe windings 32 and 40. The balance relaywould thereupon be energized to actuate the disc member 34 to effect theengagement of the contact members 36 by the bridging member 35. Acircuit would thereupon be completed from the positive conductor of thecontrol circuitthrough the switch 45 of the interrupter 15, the switch44 of interrupter 14, the switch 35, the contact members so, thencethrough two circuits inparallel, one including the trip coil 42 and theother including the operating coil 50of the transfer relay 47,controlling the bell 46, to the negative conductor of the controlcircuit.

The interrupter 14 would thereupon be opened and the relay 47 would beactuated to its biased position to complete the circuit of the bell46,thereby signalling to the station attendant that a circuit had beenautomatically disconnected from the system by reason of a faultycondition thereon. By depressing the push-button switch 53, theattendant can reset the relay 47 to render it operable for subsequentoperation.

Upon the opening of the circuit interrupt.- er 14 to disconnect thecircuit 11 from the source of energy 10, the switch 44 is opened. Thebalance relay 18 is then, therefore, inoperative to control theinterrupter 15 of. the circuit 12. Balance protection is still obtained,however, between the circuits 12 and 13 by means of the balance relay20, since the windings 31 and 39 of that relay are energized from thecurrent transformer 24 and the windings 32 and 40 are energized from thecurrent transformer 25. If the circuit 13 should now be disconnected byreason of abnormal conditions therein, the

,. interrupter 16 would be opened and the control circuits of all of thebalance relays would be open c-irouited and the relays renderedinoperative to control any of the oil Undersuch conditions, the overloadrelay 19 would provide overload protection for the circuit 12.

So long as balanced current conditions obtain in the three or moretransmission circuits, the balance relays will not operate to disconnectany of the circuits, irrespective of the amount of current traversingthe same. Under such conditions, the overload relays provide overloadprotection for the respective circuits.

It will'be noted that a balance relay is associated with each twosuccessive transmission circuits arranged as a pair of circuits to beprotected by the associated relay. For the sake of simplicity, I haveshown but one phase of the system involved. Similar protection would beprovided for the other phases of the circuits to be protected;

l Vhile I have shown a system of protection containing a, particulartype of relay, I do not limit my invention to the particular relays thatare illustrated orto the particular arrangement thereof, sincemodilications may be made therein without departing from the spirit andscope of the ap pended claims. q 7 I claim as my invention: I 1Q'1hecombination with a plurality of parallel-connected conductors betweentwo points of an electrical system and circuit interrupters for therespective conductors, of an induction relay for selectively controllingeither interrupter depending upon the occurrence of a fault thereonaffecting a predetermined ratio between the currents normally traversingthe conductors, said relay comprising a controlling member movable intwo directions, two di'lferentiallyncting windings, a windingco-operating with the differential windings to actuate themovable memberin one direction or the other depending upon the degree of energizationof the differentially-acting windings and means for energizing the saidwinding in accordance with the variation from a predetermined ratio ofthe currents traversing thepair of conductors, said means serving alsoto introduce an electrical angular displacement between the magneticflux established by the said winding andthe flux established by thedifferentially-acting windings, the fluxes cooperating to effect.movement of the movable member, in a time interval dependent upon thedegree of energi'zation of said winding.

2. The combination with a plurality of parallel-connected conductors andcircuit interrupters for the respective conductors, of means normallybalanced when the currents traversing the conductors bear predeterminedrelations to each other and means comprising a saturated transformercontrolled by currents proportional to the main currents traversing theconductors for controlling said balanced means and for introducing atime element and a directional element in the operation thereof.

3. In an electrical system, the combination with a plurality of parallelcircuit conductors, circuit interrupters therefor and currenttransformers energized therefrom, of

means for selectively controlling the interrupters upon the occurrenceof a fault in one termined ratio between the currents of the severalcircuits comprising a balance relay provided with two windings, eachenergized from a current transformer in eachconducllC of the conductorstending to affect a prede- I tor, and a co-operating winding foractuating the relay to select one or the other circult lnterrupter, anda control element also energized from the same current transformers forcontrolling the energization of the co-operating windings to introduce adirection selective action and an inverse time interval in the relaysresponsiveness.

4. In an electrical system, the combination with a plurality of parallelcircuit conduc tors, circuit interrupters therefor and cur renttransformers energized therefrom, of means for selectively controllingthe interrupters upon the occurrence of a fault in one of the conductorstending to affect a predetermined ratio between the currents of theseveral circuits comprising a balance relay provided with two windings,each energized from a current transformer in each conductor, and aco-op'erating winding for actuating the relay to select one or the othercircuit interrupter, and means for influencing said Winding comprisingan element responsive to the difference between the two circuit currentsandan element associated therewith for introducing a saturatingcharacteristic to the influence of said element upon I the windingthereby to introduce a selective and time delay action in theco-operation between said winding and the two differential windingz 5.An electric protective relay comprising an electromagnet provided withtwo windings differentially operative and adapted to be connected to twonormally current-balanced circuits, a movable member, a winding for'co-op'erating with the diiferential windings to actuate the movablemember in one direction or the other, and means co-operative with theseveral windings for influencing theselective action and introducing atime element in the response.

In testimony whereof, I have hereunto subscribed my name this 31st dayof March,

HARVEY P. SLEEPER.

